op-node/p2p: Fix flaky TestDiscovery

Prevously the test waited for the first two peer connections rather than waiting for the two expected peers to connect.
Commonly the bootnode will connect inbound to peerB at the same time as peerB connects outbound to the bootnode, resulting in two connection events.

go.mod

@@ -32,6 +32,7 @@ require (
 	github.com/urfave/cli v1.22.9
 	github.com/urfave/cli/v2 v2.17.2-0.20221006022127-8f469abc00aa
 	golang.org/x/crypto v0.6.0
+	golang.org/x/exp v0.0.0-20230213192124-5e25df0256eb
 	golang.org/x/term v0.5.0
 )
 
@@ -174,7 +175,6 @@ require (
 	go.uber.org/fx v1.19.1 // indirect
 	go.uber.org/multierr v1.9.0 // indirect
 	go.uber.org/zap v1.24.0 // indirect
-	golang.org/x/exp v0.0.0-20230213192124-5e25df0256eb // indirect
 	golang.org/x/mod v0.8.0 // indirect
 	golang.org/x/net v0.7.0 // indirect
 	golang.org/x/sync v0.1.0 // indirect

op-node/p2p/host_test.go

@@ -19,6 +19,7 @@ import (
 	mocknet "github.com/libp2p/go-libp2p/p2p/net/mock"
 	tswarm "github.com/libp2p/go-libp2p/p2p/net/swarm/testing"
 	"github.com/stretchr/testify/require"
+	"golang.org/x/exp/slices"
 
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/p2p/enode"
@@ -314,19 +315,22 @@ func TestDiscovery(t *testing.T) {
 
 	// B and C don't know each other yet, but both have A as a bootnode.
 	// It should only be a matter of time for them to connect, if they discover each other via A.
-	var firstPeersOfB []peer.ID
-	for i := 0; i < 2; i++ {
+	timeout := time.After(time.Second * 10)
+	var peersOfB []peer.ID
+	// B should be connected to the bootnode (A) it used (it's a valid optimism node to connect to here)
+	// C should also be connected, although this one might take more time to discover
+	for !slices.Contains(peersOfB, hostA.ID()) || !slices.Contains(peersOfB, hostC.ID()) {
 		select {
-		case <-time.After(time.Second * 30):
-			t.Fatal("failed to get connection to B in time")
+		case <-timeout:
+			var peers []string
+			for _, id := range peersOfB {
+				peers = append(peers, id.String())
+			}
+			t.Fatalf("timeout reached - expected host A: %v and host C: %v to be in %v", hostA.ID().String(), hostC.ID().String(), peers)
 		case c := <-connsB:
-			firstPeersOfB = append(firstPeersOfB, c.RemotePeer())
+			peersOfB = append(peersOfB, c.RemotePeer())
 		}
 	}
-	// B should be connected to the bootnode it used (it's a valid optimism node to connect to here)
-	require.Contains(t, firstPeersOfB, hostA.ID())
-	// C should be connected, although this one might take more time to discover
-	require.Contains(t, firstPeersOfB, hostC.ID())
 }
 
 // Most tests should use mocknets instead of using the actual local host network